diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-6.1/950-0900-drivers-spi-Fix-spi-gpio-to-correctly-implement-sck-.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-6.1/950-0900-drivers-spi-Fix-spi-gpio-to-correctly-implement-sck-.patch | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-6.1/950-0900-drivers-spi-Fix-spi-gpio-to-correctly-implement-sck-.patch b/target/linux/bcm27xx/patches-6.1/950-0900-drivers-spi-Fix-spi-gpio-to-correctly-implement-sck-.patch new file mode 100644 index 0000000000..ff8471411f --- /dev/null +++ b/target/linux/bcm27xx/patches-6.1/950-0900-drivers-spi-Fix-spi-gpio-to-correctly-implement-sck-.patch @@ -0,0 +1,150 @@ +From 380c336af070edf85826abbb0057bf92a03ec466 Mon Sep 17 00:00:00 2001 +From: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com> +Date: Wed, 1 Mar 2023 17:57:11 +0000 +Subject: [PATCH] drivers: spi: Fix spi-gpio to correctly implement + sck-idle-input + +Formerly, if configured using DT, CS GPIOs were driven from spi.c +and it was possible for CS to be asserted (low) *before* starting +to drive SCK. CS GPIOs have been brought under control of this +driver in both ACPI and DT cases, with a fixup for GPIO polarity. + +Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com> +--- + drivers/spi/spi-gpio.c | 74 +++++++++++++++++++++++++++++------------- + 1 file changed, 51 insertions(+), 23 deletions(-) + +--- a/drivers/spi/spi-gpio.c ++++ b/drivers/spi/spi-gpio.c +@@ -37,6 +37,7 @@ struct spi_gpio { + struct gpio_desc *mosi; + bool sck_idle_input; + struct gpio_desc **cs_gpios; ++ bool cs_dont_invert; + }; + + /*----------------------------------------------------------------------*/ +@@ -233,12 +234,18 @@ static void spi_gpio_chipselect(struct s + gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL); + } + +- /* Drive chip select line, if we have one */ ++ /* ++ * Drive chip select line, if we have one. ++ * SPI chip selects are normally active-low, but when ++ * cs_dont_invert is set, we assume their polarity is ++ * controlled by the GPIO, and write '1' to assert. ++ */ + if (spi_gpio->cs_gpios) { + struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select]; ++ int val = ((spi->mode & SPI_CS_HIGH) || spi_gpio->cs_dont_invert) ? ++ is_active : !is_active; + +- /* SPI chip selects are normally active-low */ +- gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); ++ gpiod_set_value_cansleep(cs, val); + } + + if (spi_gpio->sck_idle_input && !is_active) +@@ -254,12 +261,14 @@ static int spi_gpio_setup(struct spi_dev + /* + * The CS GPIOs have already been + * initialized from the descriptor lookup. ++ * Here we set them to the non-asserted state. + */ + if (spi_gpio->cs_gpios) { + cs = spi_gpio->cs_gpios[spi->chip_select]; + if (!spi->controller_state && cs) + status = gpiod_direction_output(cs, +- !(spi->mode & SPI_CS_HIGH)); ++ !((spi->mode & SPI_CS_HIGH) || ++ spi_gpio->cs_dont_invert)); + } + + if (!status) +@@ -336,6 +345,38 @@ static int spi_gpio_request(struct devic + return PTR_ERR_OR_ZERO(spi_gpio->sck); + } + ++/* ++ * In order to implement "sck-idle-input" (which requires SCK ++ * direction and CS level to be switched in a particular order), ++ * we need to control GPIO chip selects from within this driver. ++ */ ++ ++static int spi_gpio_probe_get_cs_gpios(struct device *dev, ++ struct spi_master *master, ++ bool gpio_defines_polarity) ++{ ++ int i; ++ struct spi_gpio *spi_gpio = spi_master_get_devdata(master); ++ ++ spi_gpio->cs_dont_invert = gpio_defines_polarity; ++ spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect, ++ sizeof(*spi_gpio->cs_gpios), ++ GFP_KERNEL); ++ if (!spi_gpio->cs_gpios) ++ return -ENOMEM; ++ ++ for (i = 0; i < master->num_chipselect; i++) { ++ spi_gpio->cs_gpios[i] = ++ devm_gpiod_get_index(dev, "cs", i, ++ gpio_defines_polarity ? ++ GPIOD_OUT_LOW : GPIOD_OUT_HIGH); ++ if (IS_ERR(spi_gpio->cs_gpios[i])) ++ return PTR_ERR(spi_gpio->cs_gpios[i]); ++ } ++ ++ return 0; ++} ++ + #ifdef CONFIG_OF + static const struct of_device_id spi_gpio_dt_ids[] = { + { .compatible = "spi-gpio" }, +@@ -346,10 +387,12 @@ MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids) + static int spi_gpio_probe_dt(struct platform_device *pdev, + struct spi_master *master) + { +- master->dev.of_node = pdev->dev.of_node; +- master->use_gpio_descriptors = true; ++ struct device *dev = &pdev->dev; + +- return 0; ++ master->dev.of_node = dev->of_node; ++ master->num_chipselect = gpiod_count(dev, "cs"); ++ ++ return spi_gpio_probe_get_cs_gpios(dev, master, true); + } + #else + static inline int spi_gpio_probe_dt(struct platform_device *pdev, +@@ -364,8 +407,6 @@ static int spi_gpio_probe_pdata(struct p + { + struct device *dev = &pdev->dev; + struct spi_gpio_platform_data *pdata = dev_get_platdata(dev); +- struct spi_gpio *spi_gpio = spi_master_get_devdata(master); +- int i; + + #ifdef GENERIC_BITBANG + if (!pdata || !pdata->num_chipselect) +@@ -377,20 +418,7 @@ static int spi_gpio_probe_pdata(struct p + */ + master->num_chipselect = pdata->num_chipselect ?: 1; + +- spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect, +- sizeof(*spi_gpio->cs_gpios), +- GFP_KERNEL); +- if (!spi_gpio->cs_gpios) +- return -ENOMEM; +- +- for (i = 0; i < master->num_chipselect; i++) { +- spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", i, +- GPIOD_OUT_HIGH); +- if (IS_ERR(spi_gpio->cs_gpios[i])) +- return PTR_ERR(spi_gpio->cs_gpios[i]); +- } +- +- return 0; ++ return spi_gpio_probe_get_cs_gpios(dev, master, false); + } + + static int spi_gpio_probe(struct platform_device *pdev) |